Tumblr Added A Very Important Security Feature And You Should Enable It Right Away

Two-step authentication is a way for websites to verify that you
are who you say you are when you try to log in. Once you set it
up, the site will often text you a verification code when it
notices that you're trying to log in from a new computer.

Gmail, Twitter and LinkedIn use two-step authentication, and now
Tumblr can be added to the growing list list.